I'm in OK and our springs and summers are blazing hot. I carry a Glock 29 in Skip Ritchie OWB holster under a simple t-shirt. His holsters hid very tight to the body and I have zero printing unless my shirt is unusually thin material. If I feel I'm printing too much, I wear an under armor style shirt underneath my t.
The 29 is another .10" thicker than the 26/27. Skip's delivery time was only about 20 days, and his price was very reasonable for the exceptional quality I received. The leather is simply beautiful and the fit is prefect. It was a bit tight at first, but loosened to a perfect degree in a couple days wearing it.
I highly recommend any product Skip puts out! He was also Lou Alessi's designer and protege, so he has almost the same holsters as Alessi, but higher quality, shorter wait time, and for about the same price.
I am now a certified Ritchie Leather fanboy!!
Edit- I carry at 3:00 or 4:00, depending on my shirt material.